Dec. 2005E-upgrade GDE Frascati1 “Energy Upgrade Scenario TG” Report L.Lilje, T.Raubenheimer and N.Toge Full Report: e_papers:white_papers_home e_papers:white_papers_home Additional info:

Dec. 2005E-upgrade GDE Frascati2 Option 1234  1 Tunnel ~41km ~22km~41km  1 Linac Installation ~22km Upstream Half ~24.4km Upstream Half ~22km Whole ~22km Sparcified  1 Nominal Gradient w. full current 31.5MV/m28MV/m31.5MV/m  1 Energy Reach 500GeV500GeV (~560GeV w. reduced current) 500GeV Options that were considered

Dec. 2005E-upgrade GDE Frascati3 Option 1Option 2Option 3Option 4 Can the RF sources and cryogenics for Phase-2 be installed during Phase-1 operation? Yes NoYes During Phase-1, is significant flexibility still reserved for the details of the Phase-2 RF and cryosystems? Yes Yes, but mildly limited, because of the fixed geometry. Setup of machine in initial phase (machine protection, quench handling etc) -Easier than Options 1, 3, 4 -- CMS Energy with 20% margin on accelerating gradient (i.e. 28 MV/m) 450 GeV500 GeV450 GeV Do impacts of Phase-2 tunnel excavation during Phase- 1 operation need to be evaluated? No YesNo Is recommissioning needed for e- sources (and likely DRs) in Phase-2? No YesNo Can the benefits of diagnostic section be accommodated? Yes Yes, also built-in rooms during Phase- 1. Any issues with 31-36MV/m hybrid operation?OK Any issues with ~40MV/m hybrid operation?OK

Dec. 2005E-upgrade GDE Frascati4 Option 1Option 2Option 3Option 4 Cost Ratio (reported at Snowmass 2005) - Phase-1 Construction - Phase-2 Upgrade - Phase-1 & 2 Total Construction Cost Ratio (when linac costs for linac cavity systems, including the cryostats, and tunnels are independently varied by up to 40%) - Phase-1 Construction - Phase-2 Upgrade - Phase-1 & 2 Total Construction 1.13~ ~0.79 ~ ~ ~0.73 ~ ~0.92 ~ Ratios of the “Guesstimated” construction cost for the linac HW and the linac tunnels. Note 1: No costs included for FFs and Inj, DR ! Note: 2: No costs included for possible RF rework in Phase 1  Phase 2, for instance, with Option 2 !!

Dec. 2005E-upgrade GDE Frascati5 Recommendations as submitted to GDE EC Recommend Option 1 –Option 1 offers good operability during Phase-1, adequate provision for beam diagnostic capabilities and ability to accommodate upgraded SRF hardware components relatively seamlessly. –Option 1, being conceptually the simplest among the schemes considered here, helps GDE develop the solid understanding of the practical fundamentals of the engineering designs and the cost analyses the most rapidly. –Much of the understanding on the engineering and the cost, to be gained from the exercise with Option 1, can be readily applied to examine the technical and cost implications of other Options soon thereafter, if deemed adequate.

Dec. 2005E-upgrade GDE Frascati6 Remarks to GDE EC (1) Concerning Option 3: –Option 3 offers the lowest cost for Phase-1 yet it requires the highest cost for the whole Phases 1&2, because of the staged civil construction and relocation of the injector systems. –Phase-2 upgrade for Option 3 is likely to take the longest time period, because of, again, the staged civil construction and the fact that the installation of RF source components cannot start till the extension tunnels are complete. –The relative merit of Option 3 will have to be looked at in the context of the project acceptance from the political or long-term financial standpoint. Such analysis can be done after the complete Option 1 study is done. (NT comment: Implications on the prospects for physics programs also need to be looked at, but our TG report did not specifically touch on it).

Dec. 2005E-upgrade GDE Frascati7 Remarks to GDE EC (2) Concerning Option 4: –Option 4 offers the operability and upgradeability similar to those of Option 1, plus substantially more diagnostic sections during Phase-1. –At this point, however, the task group does not see convincing technical justification for this option.

Dec. 2005E-upgrade GDE Frascati8 Remarks to GDE EC (3) Concerning the Energy and Acc Gradient: –Assumed accelerating gradient of 31.5MV/m for Phase-1 and 36MV/m for Phase-2 are a major challenge. –Vigorous, coherent and organized international collaboration programs are mandatory to establish especially the quality control measures which reduce the performance scatter currently observed. –A detailed list of R&D topics has been established in the WG5 Snowmass reports, as well as in BCD.